Energy deals coherence checker

There is a lot of confusion and misinformation about UK electricity and gas deals, especially from a low user's point of view.

Comparison sites sometimes fail to ask for all your figures (e.g. Economy 7 night readings), instead estimating them based on a "typical" household. Therefore, their final answers can be wrong and need checking.
- (We can't rule out the possibility that those hidden estimates are biased in favour of whatever company pays the site the most, or even against your current supplier---if they get paid every time you switch then they won't want to say "stay put". But even if there is no bias, estimates can be wrong so check the real figures.)
Journalists can panic about short-lived price-fix deals, whereas in your case it might be better to stay on a good variable price (see the note after the results below).

This page is a quick "reasonableness checker" of energy deals. It uses Javascript, so programmers can see how it works by viewing this page's source code; no hidden calculations are done on the server.

Enter two sets of meter readings, 12 months apart:
	Reading 1	Reading 2
Day
Night (if any)
Gas (if any)
Gas meter type (if any)
Gas calorific value (MJ/m3)
Gas volume conversion
Enter the details of the two deals you want to compare:
	Deal 1	Deal 2
Primary day rate	p	p
Secondary day rate (if any; banned in UK 2014)	p	p
If there's a secondary rate, enter the number of primary-rate units per quarter
Night rate (if any)	p	p
Gas primary rate (if any)	p	p
Gas secondary rate (if any; banned in UK 2014)	p	p
Gas threshold for secondary rate (kWh/quarter) if any
Standing charge per day (if any)	p	p
VAT percentage (if not included)	%	%
Dual-fuel proportional discount (if any; banned in UK 2014-2016)	%	%
Fixed discount (if any)	£	£
Payment method discount (if any; banned in UK 2014-2016)	%	%
Paperless discount (if any; banned in UK 2014-2016)	%	%
Now press:	(or )
Annual bill
Percentage difference

If the cheaper deal is variable and the more expensive deal is fixed, you might find that the percentage increase you get from fixing is actually a lot more than the percentage the variable prices are expected to rise. You need to check with your figures though.

This calculator is not financial advice; I hope it's useful but I do not accept legal responsibility for any decisions based on its results.

All material © Silas S. Brown unless otherwise stated.
Javascript is a trademark of Oracle Corporation in the US.
Any other trademarks I mentioned without realising are trademarks of their respective holders.